The USC/UCLA Center on Biodemography and Population Health (CBPH) supports unique interdisciplinary collaboration among a multidisciplinary group of researchers devoted to understanding population health. The CBPH incorporates 2 primary sites - at the Andrus Gerontology Center of the University of Southern California and the Multicampus Program in Geriatric Medicine and Gerontology in the School of Medicine of the University of California at Los Angeles. The primary purpose of CBPH is to provide a synergistic research environment to encourage research incorporating a variety of disciplines such as epidemiology, clinical geriatrics, biostatistics, psychology and biology into models of the health status of populations and the expected life cycles of individuals. The integration of biological, epidemiologic and medical risk information into demographic models is fundamental to understanding and projecting demographic trends and differences in population health. In addition, the application of the demographic perspective to medical, epidemiological, and biological knowledge is central to evaluating the relative importance of the various determinants of population health.